1. Field of the Invention
The invention generally relates to an electronic gaming apparatus, such as a slot machine, which displays combinations of indicia to identify a game's outcome.
2. Description of the Related Art
Conventional gaming devices have been proposed which include a plurality of reels that rotate about a common axis and include indicia (such as fruit, bars, stars and the like) about their peripheries that are used to indicate the stopping position of each reel. These reels are rotatably activated by pulling a lever and are stopped randomly to define a game outcome. As each stopping position upon each reel was randomly defined, the odds of each potential outcome were the same, namely 1:N (where N represents the total number of possible indicia combinations). Thus, if each reel included 22 indicia about its periphery and the gaming device included three reels, the total number of possible combinations N equaled 22.sup.3 or 10,648.
However, as the demand increased to provide larger jackpots, the need arose for gaming devices capable of generating outcomes having a lower probability of occurring (such as 1:1,000,000). To increase the odds in thee conventional mechanical gaming devices, it is necessary to include either additional reels or more indicia (e.g. stopping positions) upon each reel.
Alternative gaming devices have been proposed (such as in U.S. Pat. No. 4,448,419) which utilize "virtual reels" to increase the odds of a particular outcome without increasing the number and size of reels. The gaming device of the '419 patent includes a standard number of reels with an ordinary number of indicia thereon (e.g. 3 reels with 22 positions per reel). These standard reels provide the typical number of potential physical outcomes (e.g. 10,648). Additionally, this virtual reel type gaming device includes a random number generator capable of computing a random number for each reel from a small set of numbers (e.g. 1 to 100). Each number within the random number set represents a virtual reel position, and thus the combination of each set of virtual reel positions produces a gaming device having an extremely large number of stopping points or outcomes (e.g. 1 to 1,000,000). Hence, the final combination of virtual reel outcomes, has an extremely low probability of occurrence (e.g. 1:1,000,000 in the current example).
The virtual reel type gaming device of the '419 patent further includes virtual reel tables for each standard reel, in which each virtual reel position is assigned to an actual/physical position upon each standard reel. In the example, a standard reel includes 22 positions while the virtual reel includes 100. Thus, multiple positions within the virtual reel are assigned to the same position upon the actual reel. This virtual reel table provides a mechanism for varying the odds of occurrence for an actual reel position by assigning different numbers of virtual reel positions to each actual reel position. For instance, a jackpot "bar" upon the actual reel may be assigned to one virtual reel position (i.e. one random number).
During operation, the virtual reel type gaming machine obtains a number from the random number generator and uses this number as an index into the virtual reel table to obtain a corresponding actual reel position. Thereafter, the standard physical reel within the gaming machine is stopped at the indexed actual reel position. This process was repeated for every reel within the machine, after which the outcome is determined from the chosen reel positions.
However, the virtual reel type gaming machines include inherent limitations. First, the machine must include sufficient memory to store the virtual reel table. Thus, as the demand increases for larger payouts with lower probabilities of occurrence, the size of the virtual reel table will increase along with memory requirements therefor. Additionally, once the virtual reel table is established, it is not amenable to updates without completely rewriting the table. For instance, in the virtual reel table of the '419 patent, consecutive random numbers are assigned to each actual reel position. Thus, if the system is modified to change the number of actual positions upon the reel or to change the tonal number of virtual positions, the entire virtual reel table must be rewritten.
Further, these conventional gaming devices require the virtual reel table to be rewritten when it is desirable to change the odds of a particular reel occurrence. Finally, as the market for gaming devices changes, it is desirable to add extra indicia combinations to existing reels and to add more reels with new indicia. These additions extend beyond the capabilities of the virtual reel systems. Also, the market for gaming devices now requires more than one set of virtual reels to be contained within each computer. As these additions arise, they further increase the memory requirements of the gaming machine.
The need remains in the industry for an improved design and implementation technique to address the problems and drawbacks heretofore experienced. The primary objective of this invention is to meet this need.